Field of the Invention
The invention relates to a bridge module which is connected between at least two bus systems and is suitable for serial data transfer of binary data from one of the bus systems to at least one other of the bus systems.
Such bus systems may be, for example, local computer networks. In such bus systems or local computer networks, which are increasingly used in motor vehicle electronics, a subscriber station communicates via a data bus with at least one other subscriber station which is connected to the same data bus. See, for instance, German publication DE 35 06 118, which discloses a so-called Controller Area Network (CAN network). The CAN network is an example of such a bus system.
With the increasing requirement for electronic components in motor vehicles, it is advantageous to use more than two local bus systems, for example at different data transmission rates. This also, of course, results in an increased requirement for subscriber stations of different bus systems to be able to communicate with one another. A so-called bridge module may be provided, for example, for the purpose of data transfer between different bus systems.
A bridge module of the above type and which is suitable for data transfer between different bus systems has been described in Jens Eltze, "Double CAN Controller as Bridge for Different CAN Networks," 4th Int'l Conference, Berlin, 10/1997, pages 15-17 to 15-19. There, particularly in FIG. 1, a technical implementation is presented of a programmable bridge module which, for the purpose of data transfer and for data filtering, is arranged between the subscriber stations of two CAN bus systems.
The programmable bridge module described there has a similar characteristic to a central processing unit (CPU) and thus allows data to be processed and handled. A separate micro-processor is required there, to provide an additional CPU for the data transfer and for data filtering. An additional microprocessor, which is used exclusively for the data transfer between different bus systems, is, however, extremely costly.